Proposed are two randomized longitudinal research experiments examining the effect of Advance Directives on health care and health care costs in patients recruited from the University of California, San diego Medical Center and affiliated hospitals. Part I involves continuing follow-up of 204 patients with life threatening illnesses - chronic renal disease, chronic pulmonary disease, heart disease, AIDS, and cancer - who were randomly assigned to an experimental group (offered an Advance Directive - the California Durable Power of Attorney for Health Care) or a control group (not offered an Advance Directive). This study is a continuation of a research experiment exploring alternatives to health care rationing as a solution to rising costs among very ill patients. We will continue following these patients longitudinally in order to enhance the power of the analyses. Part II involves 200 patients with life-threatening AIDS and cancer who will be offered an Advance Directive and two instruction supplements, a Procedure-Oriented instruction supplement and a Quality-of-Life instruction supplement, as a means of communicating their wishes regarding terminal care. Only patients who complete and return the Advance Directive and the Instruction Supplements will be followed in the study and they will be randomly assigned to have one of these Supplements as well as the Advance Directive inserted in their medical record. After the initial contact, patients and physicians will be interviewed at regular six month intervals and at hospitalizations. This proposal is significant in that it will provide the first attempt to gain insight into two strikingly different approaches to enhancing patient-physician communication through Advance Directives. Our major hypotheses are that enhancing personal autonomy through the enactment of Advance Directives will reduce the cost of health care without diminishing well-being, and that improvement in patient-physician communication through Quality-of-Life instruction supplements to Advance Directives will result in changes in physician behavior more in keeping with patients' wishes regarding terminal treatment. Confirmation of the major research hypotheses may have beneficial consequences for patient-physician communication regarding terminal care treatment decisions and for the health care system generally by changing the focus of thinking currently prevalent among health policy makers. Solutions to the rising costs of medical care would be considered less in terms of imposing limits and more in terms of enhancing patient autonomy and improving communication by patients to physicians.